“Kim Jong-un would like to have a demonstrated ability to hold the United States homeland at risk with the threat of nuclear war.”

The North Korean leader has been engaged in an escalating war of words with US President Donald Trump, who pledged to ensure the denuclearisation of North Korea to re-establish calm in East Asia.

But Dr Kroenig – who has served in several positions within the US Department of Defense – warned Kim is unlikely to heed calls to give up his arsenal.

Speaking to ABS-CBN News, the Georgetown associate professor said: “I think he wants to demonstrate he has an operational nuclear-armed intercontinental ballistic missile and he is not quite there yet.

“Getting there will require more missile tests and more nuclear tests.”

North Korea recently accepted offers to reopen diplomatic channels with South Korea by accepting to send a delegation to the Winter Olympics scheduled for February in PyeongChang.

But despite Kim Jong-un’s diplomatic turn, President Trump deployed nuclear bombers to the Andersen Air Force Base on Guam to monitor North Korea during the Olympics.

The US overseas territory of Guam stands barely 3,430km (2131 miles) from North Korea and has been previously under threat of missile attacks from Pyongyang.

The nuclear-capable B-2 Spirit bombers join several conventional B-1 Lancer bombers on Guam in support of US Pacific Command’s deterrence and assurance mission in the Pacific.